Microbial Analysis of Processed Foods Stored in Domestic Refrigerators of Selected Eateries in Ile-Ife, Osun State, Nigeria

Odewade Joseph Oluwaseun

doi:10.11648/j.bio.20180603.11

Abstract

Consumption of contaminated refrigerated foods is increasing the incidence of food-borne diseases globally. However, there is paucity of data on prevalence of microbes associated with these foods from Osun State, Nigeria, thus, the need for isolation and characterization of microbes associated with refrigerated foods from this region. A total of 80 processed food samples were collected aseptically and refrigerated for four days. Samples were analyzed for the presence of bacteria and fungi while antibiotic resistance patterns of bacterial isolates were determined using standard methods. Mean bacterial count ranged from 7.0 x104 to 3.7 x105 cfu/ml with highest bacterial count of 3.7 x 105 cfu/ml obtained from melon soup sample, while least count of 7x104 cfu/ml was obtained from cooked meat. Fungal count ranged from 2.0 x 102 to 5.6 x103 sfu/ml with cooked beans having the highest count of 5.6 x 103 sfu/ml. The bacteria that were isolated from refrigerated processed food samples include Corynebacterium kutscheri (47.05%), Bacillus spp (14.70%), Staphylococcus aureus (11.76%), Lactobacillus fermenti (5.8%), Aeromonas hydrophila (5.8%), Pseudomonas spp (5.88%), Lactobacillus casei (2.94%), Lactobacillus delbrueckii (2.94%) and Citrobacter freundii (2.94%), while fungi isolated were Aspergillus fumigatus (24.56%), Aspergillus niger (21.05%), Aspergillus flavus (14.04%), Aspergillus brevipes (14.04%), Mucor spp (7.02%), Penicillium spp (8.77%) and Saccharomyces spp (10.53%). Corynebacterium kutscheri had the highest resistance of 17(37%) while Lactobacillus casei showed no resistance (0%) to the antibiotics used. This study showed high bacterial and fungal counts from the analyzed samples, hence, the need to ensure hygienic food processing and refrigerating conditions.

Highlights

Foods refrigerated can become vectors for food-borne illness by contamination with food-borne pathogens in retail stores, processing plants, or consumers’ homes [1]
Five refrigerated food samples were analyzed for the presence of bacteria and fungi with standard plate count method used for the analysis
The bacterial count ranged from 7x104 to 3.7x105 cfu/ml with highest bacterial colony count obtained from soup (3.7x 105 cfu/ml) while the least colony count of 7.0x104 cfu/ml gotten from analyzed meat sample

Summary

Introduction

Foods refrigerated can become vectors for food-borne illness by contamination with food-borne pathogens in retail stores, processing plants, or consumers’ homes [1]. These spoilage-causing or pathogenic microorganisms are often able to grow at low temperatures and lead to reduction of shelf life or even affect consumer’s health [2,3]. The perishable raw or cooked food that could serve as a growth medium must be stored to prevent the multiplication of bacteria that have survived during processing or handling [4]. Different food requires different places and temperature for storage [5]. Despite low Odewade Joseph Oluwaseun et al.: Microbial Analysis of Processed Foods Stored in Domestic

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Discussion

Conclusion